Torque responsive linear actuator



Jan. 28, 1969 B. c. WOLFE 3,424,058

TORQUE RESPONSIVE LINEAR ACTUATOR I Filed March 21, 1966 Sheet of 2(@(mmp r t 5: Qfl \2 if A i I 2 a B I \V IG. I v I v I 9 l6 I 4 I 2o 52:18:- 0

:54 I 5 58 +3 46 4 INVENTOR.

44 BY BARON o, WOLFE FIG. 2 l w'as-r.ml lnmwnsuu) Jan. 28, 1969 A BC.WOLFE 3,424,058

TORQUE RESPONSIVE LINEAR ACTUATOR Filed March 21,

Sheet INVENTOR.

BA R0; 0. WOLFE BY mama-J amm su l ATTORNE YS United States Patent3,424,058 TORQUE RESPONSIVE LINEAR ACTUATOR Baron C. Wolfe, 24 W. GrantSt, Eureka, Calif. 95501 Filed Mar. 21, 1966, Ser. No. 535,844 US. Cl.91-105 Int. Cl. F01c 1/00; F1611 29/20 2 Claims ABSTRACT OF THEDISCLOSURE This invention relates to apparatus for controllablypositioning and driving a load along a linear path in response torotation of a hydraulically operated actuator.

Although the present invention is described hereinafter by way ofexample in connection with a Weir gate, the invention has utility in anyapplication requiring adjustable positioning of a load along a linearpath. Apparatus constructed according to the present invention can beadapted to opening and closing sliding doors,"moving aircraft controlsurfaces, such as ailerons, positioning and feeding cutting tools onmachines, and virtually any environment in which it is desired to moveor position a load along a linear path.

As shown more fully hereinafter in connection with a weir gates, theinvention includes a threaded shaft secured to a load such as a weirgate, an interiorly threaded sleeve circumscribing the shaft, and arotary hydraulic actuator for rotatively driving the sleeve. A completedescription of a rotary hydraulic actuator is disclosed in my U.S.Patent No. 3,241,456. Such patent discloses an actuator that has acylindric chamber and a lobed rrotor mounted within the chamberconcentrically thereof. Within the chamber is provided a plurality ofsliding vanes that bear against the peripheral surface of the rotor todefine various power compartments. Fluid passages are provided in theactuator for controllably delivering pressurized hydraulic fluid to thecompartments to rotatively drive the rotor. The sleeve is mountedconcentrically of the rotor so that on application of pressurizedhydraulic fluid to the device, the sleeve is rotatively driven so as toposition the shaft and the load along a linear path.

An object of the invention is to provide a remotely controllable linearactuator that can accurately and continuously position a load along apath. This object is achieved by providing a hydraulic rotary actuatorthat is capable of delivering high torque in either a forward or reversedirection of rotation and by threadedly coupling to such actuator ashaft to the end of which a load is attached.

A feature and advantage of this invention is that the force applied tothe load is uniform throughout the entire range of movement. Aconsequence of such uniform force is that the load can be accuratelypositioned at any desired point along its path of movement.

Another feature and advantage of this invention is that extremely heavyloads can be adjustably positioned. As more fully disclosed in theaforecited patent, the rotary hydraulic actuator is capable ofdelivering extremely high torque. By converting such torque to linearmotion 3,424,058 Patented Jan. 28, 1969 "ice the present inventionpermits linear positioning of large loads.

Still another feature and advantage is that close positional control ofa load can be effected by a device constructed according to theinvention. The rotary actuator, because of its symmetrical design, iscapable of rotation in either direction. Moreover, the actuator delivershigh torque at low rotative speeds. Such desirable characteristics arepreserved in converting the rotary force to a linear force, as aconsequence of which the position of the load can be established with ahigh degree of precision.

Yet another feature and advantage of this invention is that theapparatus is extremely compact, a characteristic rendering the apparatusparticularly suitable for such applications as actuating aircraftcontrol surfaces.

A further feature and advantage is that the load, once moved to adesired position, is retained in such position without braking orapplication of power until further movement of the load is desired.

Other objects, features and advantages will be more apparent onreferring to the following specification and accompanying drawings inwhich:

FIG. 1 is a perspective view of the actuator of the present invention asemployed in controllably positioning a weir gate;

FIG. 2 is a cross-sectional view of the actuator taken substantiallyalong line 2-2 of FIG. 3; and

FIG. 3 is an elevation view of the actuator, portions being broken awayalong line 33 of FIG. 2 to reveal internal details of construction.

Referring more particularly to the drawings, reference numeral 12indicates a threaded shaft carried in a rotary actuator generallyindicated at 14 for movement along a path co-extensive with thelongitudinal axis of the threaded shaft. In FIG. 1, the lower end ofshaft 12 is shown attached to a gate A that is vertically slidable ingrooves B that confront one another across an opening in a weir C. Thelinear actuator of this invention acts to vertically position gate A inproportion to the amount of water that it is desired to pass through theopening in weir C.

Rotary actuator 14 includes a casing 16 having an internal cylindricsurface 18 defining a cylindric chamber. Exterior of the cylindricchamber, casing 16 is provided with suitable mounting brackets 20 forfixing the chamber relative to the load. The cylindric chamber iscompleted by end plates 22 secured to casing 16 by any suitableexpedient, such as screws 24. Rigid with each end plate 22 andpreferably integral therewith is a hub 26 which is bored concentricallyof cylindric surface 18 to rotatively support or journal a sleeve 28.Suitable thrust bearings 30 are provided to prevent axial movement ofsleeve 28 relative casing 16, such thrust bearings being shown somewhatschematically in FIG. 3 since they are conventional elements.

Mounted on sleeve 28 interior of cylindric surface 18 is a rotor 32constituted by a body having a plurality of lobes 34 radiating therefromin uniform spaced relation around the periphery of the rotor. Theperipheral extremities of lobes 34 are formed concentrically of the axisof cylindric surface 18 and cooperate with the cylindric surface in anon-contacting fluid-sealing relation. A noncontacting fluid-sealingrelation, as more fully described in the aforecited patent, is arelation frequently employed in the hydraulic arts wherein theperipheral surface of the lobe does not contact the cylindric surfacebut is sufiiciently close to prevent hydraulic fluid from passing fromone side of the lobe to the other side. A clearance of approximately.0005 inch affords such relationship. The side surfaces 36 of rotor 32bear a similar relationship to the inner faces 38 of end plates 22; suchrelationship is exaggerated in FIG. 3 for clarity. Sleeve 28 and rotor32 are joined for rotation in unison by any suitable expedient, such asa key 40.

Although rotor 32 is shown herein as including three lobes 34 suchshowing is only exemplary, because as shown in the aforecited patent, abody having a greater number of lobes can be used. Casing 16 defines aplurality of radially extending slots 42 which are uniformly spacedaround the periphery of the casing and which slidably support vanes 44.The number of slots 42 and vanes 44 exceeds the number of lobes on rotor32, there being four slots and vanes in the embodiment herein described.For convenience of description each vane 44 will be considered as havinga clockwise face 46 and a counterclockwise face 48. Each vane is biasedinto contact with the peripheral surface of rotor 32 by a compressionspring 50 so that, as can be seen most clearly in FIG. 2, a plurality ofcompartments 52 are defined by cylindric surface 18, the peripheralsurface of rotor 32 and clockwise face 46 of the vane. Correspondingcompartments 54 are defined by cylindric surface 18, the peripheralsurface of rotor 32 and counterclockwise vane face 48.

Communication of hydrauli fluid to and from compartments 52 and 54 isestablished by respective conduits 56 and 58 formed in each vane.Circumferentially extending channels 60 and 62 are provided forcommunicating hydraulic fluid to respective conduits 56 and 58, fittings60F and 62F being provided for connection of hydraulic lines 64. Aconventional hydraulic pressure source, not shown, is provided 'forselectively supplying hydraulic fluid to one of lines 64 and dischargingthe fluid from the other line 64. The particular direction of fluid flowdetermines the direction of rotation of rotor 32 which in turndetermines the direction of lineal movement of shaft 12.

In operation, when it is desired to raise gate A for example, hydraulicfluid under pressure is applied to the line 64 that communicates withconduit 56 and compartments 52. Hydraulic fluid is exhausted fromconduits 58 which communicate with compartments 54. Such pattern offluid flow causes rotor 32 and sleeve 28 to rotate clockwise.Consequently, shaft 12 moves upwardly and opens weir gate A. Theconnection between the lower end of shaft 12 and weir gate A preventsrotation of the shaft, which is essential to effecting linear movement.Should it be desired to drive a load that is not constrained againstrotation as is weir gate A, it will be obvious that a longitudinallyextending groove can be formed in shaft 12 and that a key or like membercan be firmly affixed to casing 16 which key slides in the slot toprevent the shaft from rotating with sleeve 28.

When it is desired to lower weir gate A or like load, hydraulic fluid isapplied to the opposite fluid line 64 so that hydraulic fluid underpressure flows through conduit 58 into compartments 54, thereby to driverotor 32 in an opposite or counterclockwise direction as viewed in FIG.2.

It will be obvious that the position of weir gate A once it isestablished will be maintained without necessity for applying hydraulicfluid to the apparatus, because of the pitch of the threaded engagementbetween shaft 12 and sleeve 28. Consequently, when it is desired to movethe load along a linear path, the apparatus is energized from aquiescent state by application of hydraulic pressure to one or the otherof fluid lines 64. Since lobed rotor 32 has fewer lobes than there arevanes 48 at least one compartment 52 and/or 54 will at all times be in aproper phase for application of torque to sleeve 28 in response topressurized fluid supplied to the compartment. Consequently, closepositional control of the load secured to shaft 12 can be effected; theprecision of control possible with the present apparatus is limited onlyby the conventional apparatus provided for controllably applying thehydraulic fluid to lines 64.

As described in my Patent No. 3,241,456, rotary actuator 14 can be madevirtually any size so that loads of virtually any size can be accuratelypositioned by use of the present apparatus. Obviously the showing in thedrawings of the present invention of shaft 12 aligned in a verticalposition is only exemplary; the shaft can be mounted in any positionalong which linear movement is desired.

Thus it will be seen that the present invention provides an actuator foraccurately positioning a load along a linear path which apparatus can becontrolled remotely since it utilizes a conventional hydraulic apparatusin energizing the actuator. Moreover, because the size of the actuatorcan be constructed to almost any desired size, the amount of load andthe length of the path over which the load is positionable can beaccommodated.

Although one embodiment of the present invention has been shown anddescribed it will be obvious that other adaptations and modificationscan be made without departing from the true spirit and scope of theinvention.

What is claimed is:

1. Apparatus for positioning a load along a linear path comprising athreated shaft attached to said load and disposed in said path; aninteriorly threaded sleeve circumscribing said shaft and threadedlyengaged therewith; a hydraulic motor having a rotor in drivingconnection with said sleeve and a casing defining a cylindric chamber,said rotor being journalled for rotation in said chamber about thecylindric axis thereof, said hydraulic motor including a first pluralityof vanes mounted in said casing and extending radially inwardly intocontact with the peripheral surface of said rotor, said rotor beingformed with a second plurality of lobes radiating outwardly therefrom inuniformly peripherally spaced relation concentric with said casing, saidfirst plurality being greater than said second plurality therebyestablishing at least one compartment bounded by the surface of saidcylindric chamber, said rotor and a forward face of one said vane, andanother compartment bounded by the surface of said cylindric chamber,said rotor and the rear face of one said vane, said chamber having firstand second fluid conduits communicating with a respective one of saidcompartments so that admission of hydraulic fluid under pressure intosaid one compartment will rotatively drive said rotor in one directionand admission of hydraulic fluid under pressure into said anothercompartment will rota- References Cited UNITED STATES PATENTS 1,423,8177/1922 Pitz et al. 74-89.l5 2,400,418 5/1946 Hofbauer 91-420 X 2,748,8776/1956 Miller et al 9l-420 X 2,919,911 1/1960 Furtah 74-89.15 2,978,1294/1961 Becker 9l420 X 3,241,456 3/1966 Wolfe 91-105 OTHER REFERENCESProduct Engineering, vol. 33, No. 7, Apr. 2, 1962, Rotary to LinearMotion, Ball, R. C., pp. 68-73.

MARTIN P. SCHWADRON, Primary Examiner. IRWIN C. COHEN, AssistantExaminer.

US. Cl. X.R.

